1. Field of the Invention
The invention relates to a magneto-optical high voltage current measuring transducer utilizing a measurement sensing device carrying high potential and designed as a light conducting coil, with which linearly polarized light is rotated with respect to the direction of its polarization, in dependence upon the strength of the magnetic field which is produced by the current to be measured, whereby the rotation may be utilized as a criteria for the high voltage current to be measured.
Magneto-optical measuring transducers are known, for example, such as illustrated in German AS 1,283,363, in which polarized light is transmitted through a first Faraday rotator, which functions as a measurement sensing component, and is disposed in a magnetic field which is dependent upon the high voltage current to be measured. Upon passage through such Faraday rotator, the direction of polarization of the polarized light beam is rotated in dependence upon the effective magnetic field. The polarized light, following its passage through the Faraday rotator and changed in its polarization direction is then conducted through a second Faraday rotator, functioning as a compensator, which carries ground potential. The compensator is disposed in an adjustable magnetic field, whereby the polarized light, in its changed polarization direction, is rotated back to its original polarization direction. The strength of the adjustable magnetic field accomplishing this function thus may be utilized as a criterion for the strength of the current to be measured.
It is already known from German OS 2,130,047 to utilize a Faraday rotator as a light conductor coil. Such a light conductor coil consists of a glass fiber through which the polarized light beam is conducted which, as it passes through the glass fiber, is rotated with respect to its polarization direction in dependence upon the influencing magnetic field.
Faraday rotators of this type, designed as light conductor coils, are subject to limitations, in particular with respect to the measuring accuracy, as a result of mechanical stresses or tensions created during production and because of the curvature of the light conducting fibers, birefringence errors occur.